A recent email arrived, offering an unusual
engine for sale. I'd never seen one
like it and with the price the seller
was asking, it wasn't likely I'd be
seeing his anytime soon. It did, however,
tweak my curiosity and I did a few searches
for "Water Pressure Engines".
As luck would have it, I stumbled onto
a rough wood cut engraving of the same
engine style and after a bit of eyestrain,
I began to think it just might be possible
to build one.

Thus began the
project I'll share with you on this
page. There were no drawings and the
photo of the offered engine, along with
the very rough engraving were all I
had to work from. I hope you'll forgive
me if a bit of artistic license
was taken to make it uniquely my own
engine creation.

The available history for the
Schmidt Water pressure engine is somewhat
scant, but I've managed to piece together
some of it. The design is a unique
take on the use of an oscillating valve
system,
due to the radial configuration which
lets the horizontal cylinder rock back
and forth in a semi-circular saddle.

The original engine was built in
the mid 1800's by a Mr. Schmidt,
of Switzerland and was designed to
run on water, steam or air. The engine
was used to pump potable water to remote
villages in the Swiss Alps. It was fed
water under pressure to run the engine
and the exhausting water was fed into
the outgoing water lines with enough
pressure to make the long trip up the
mountain side. In essence, the engine
serves functions as both, the motor
and pump.

The unusual copper
dome is there to absorb the shock
of water hammer. Since water doesn't
compress, any sudden change in incoming
pressure could literally destroy the
engine. The air in the column was there
to compress and cushion the system and
prevent damage.

View
of the Water Hammer Column

The
Unique Valve Configuration

3D Rendering for Proof of Concept

The project began with a close study
of the available photo and the engraving.
Once I had a feel for what was going
on with the design, it was then modeled
out in 3d to prove my thoughts were
indeed right. Only then did I begin
the process of cutting metal. Each individual
piece was carefully marked out to match the calculations I
was able to make while modeling the
engine. The components were then
carefully machined from raw metal bar
stock, one at a time, using only manual
machining techniques. No CNC was used
in building the engine and the only
parts not hand made were the bolts
and dowel pins used to put the engine
together.

I would be remiss if I didn't come clean about now. Looking
back over the photos it's
easy to see where they could
give the mistaken impression
that everything was accomplished
without any problems. That
impression would be wrong...(grin).
An errant end mill, due
to a vise, that I forgot
to tighten, required making
a second cylinder and a
small miscalculation had
me redoing the valve blocks,
due to an improper radius
where they mated to the
cylinder. The large radius
of those interrupted boring
cuts to the base had
me sweating bullets before
I was done.

The project
was an exercise in mental
gymnastics. I was often
cornered by some procedure
that required a bit of thought
before things would work.
While working without drawings
let's you make changes on
the fly, those same changes
often beget more challenges
and changes. Luckily, I
enjoy the challenges and
although some of my solutions
might not be found in any
machinist's manual, they
worked for me and I still
have all my fingers and
toes.

With the centerline established, it was easy to relatively
easy to locate the holes for the crank
shaft, the side arm ends and the
cylinder pivots. The side arms stabilize
the cylinder, provide it with a pivot
point while allowing tension to be adjusted
on the valve blocks in order to control how they
seal and for speed control. Tthe more
tension applied, the slower the engine
can be made to run. They also allow
the cylinder to be swung out of the
way for maintenance and lubrication.

Interestingly, the
real world engine apparently used water
as the lubricant of choice and a certain
level of leakage was accepted during
operation.

First Side Arm
Fitting

Cutting
Side Arms on Rounding Table

Finished
Arms, Base Porting, Rear
Tension Bar

Studs,
Ports and Packing Gland Finish
the Cylinder

The
Tiny Rear Tension Handwheel

Making the side arms was accomplished using a slightly
modified home made tool
that Marv Klotz shared with
the members of theHMEM
hobby machinist forum. It
allowed the arm ends to
be manually rounded and
contoured, as well as making
the inner and outer tapering
cuts dead easy to do. Completing
the cylinder was a landmark
in the build, as it
marked the point were the
engine ceased to be a pile
of small parts and began
to become assemblies.

The
small handwheel was also
manually cut using my handy
dandy home made indexing
table. While I worried about
working at this small size but
it all went smoothly and without
event. When I shared this
wheel
with the guys at HMEM, I
was a little amazed to hear
30 year machinists exclaiming
that they'd never be able
to work that small. One
of them finally explained
that most job shops work with large items taking
huge cuts, espcially when compared
with my small equipment.
I had to admit working on
large stuff would intimidate
me in the same way. Who
knew?....LOL. Either
way.... it definitely added
a nice touch to the engine.

Close
Up of Small
Details as
the Engine Nears
Completion

As things progressed, the addition of small details like
pillow block bearings, working
wick oilers and decorative
end caps for the dowel
pins began to add interest
as well as functionallity
to the little engine. The
stuffing box or packing
gland was fitted and graphite
string installed to seal
the rod passage (thanks
Tim) and provide
lubrication to the piston
rod. Small locking bolts were added
to the side arms to hold
them in their proper positions
and caps were made to finish
off the small 3/16 diameter
oilers.

Progress
slowed quite a bit as these
small but important items
were made and fitted. Luckily, the
satisfaction levels made
it worth all of the seeming
lack of progress.

At this point, the engine was tested on air and found
to be in need of running in.
The crank shaft end was chucked
in my small drill press
and carefully powered, with lots of
lubrication. After about
30 minutes, the engine turned
relatively free and only
required 15 pounds of air
to run at a rather fast
clip.

Things only
got better from there. Soon
the engine would run at
a nice comfortable speed
on as little as 5 PSI, even
with the tension set fairly
heavy
on the valve blocks. The
engine now turns over by
hand with an almost totally
undetectable level of friction

Water
Pressure Engine After
Running In

The engine obviously looks a little naked without a flywheel.
After all the time I'd studied
it, a single flywheel just
wasn't going to finish the
engine. I decided to make
a pair of them and as luck
would have it, a friend
in the UK provided me with
a copy of Philip Duclos'
instructions for manually
making curved spoke versions.
It didn't seem like such
a huge step after the tiny
handwheel so I took up the
challenge and decided to
give it a try.

The
instructions were perfect
and well thought out, so
I soon had a matching set
of S spoked flywheels ready
to fit up to the engine.
What is that you say?....
uh... yeah... the instructions
were for curves. Uh...yeah...
I did say "S"
spokes.

Okay...
one last confession....LOL.
While making the curved
spokes, my indexing table
slipped (my fault for climb
cutting) and the end mill
came to a stop in the middle
of the previous spoke. One
of those AWWW *&@$#
moments for sure. Luck was
on my side. The mistake
turned out to be the exact
way to make classic S style
spokes.

This project is my second engine and took from April until
September to complete..
While the first engine project
turned out ok, this one
came much closer to my
self expectations and boosted
my confidence. I now
have little fear that I
can accomplish just about
anything that I can imagine.
I'm pleased with the
results and I hope you too
approve of how things turned
out. Thanks for sharing
in the fun.